D4Sign API vs SignRequest

D4Sign API has no write-up on Specifiction yet; its figures are above.

SignRequest is an online e-signature tool for preparing and signing contracts and other documents without printing and scanning. Users can upload PDF, Word, or Excel files and add text, dates, checkmarks, and signature fields. Signers can draw or upload a signature, type their name, or use a generated signature. Workflows can set signing order, select authorization methods, and request attachments. My Documents tracks document status and stores files, while reusable templates keep settings such as signing order and notifications. SignRequest supports signing on smartphones, laptops, and tablets, with Android, iOS, web, and API access. Its free plan allows 10 documents per user per month and unlimited signatures. Professional costs €9 a month per user; Business costs €15 a month per user. Both paid plans describe unlimited documents subject to fair use, and high-volume sending may require a separately sold document bundle. Business API access has additional fees and requires a Business account. Listed integrations include Zapier, Slack, Google Workspace, Google Drive, and others. The service states it is ISO 27001 certified and is in the process of obtaining HIPAA certification.